Field of the Invention: The present invention relates to fetal heart rate monitoring using fetal scalp electrodes. More particularly, the present invention relates to a disposable fetal scalp electrode assembly including a connector, a reusable cable assembly configured for cooperatively engaging the connector, a system including the fetal heart rate electrode assembly and the reusable cable assembly, and methods of use.
State of the Art: Fetal heart rate monitoring during labor has been an accepted medical practice for decades. The most favored techniques are those which employ an electrode in contact with the fetus.
One noteworthy apparatus for effecting such fetal contact is disclosed in U.S. Pat. No. 3,827,428 (Re 28,990) to Hon et al., the disclosure of which is incorporated herein by reference. In the Hon apparatus, a first, spiral electrode is carried at the distal end of a drive tube slidingly received within a larger diameter guide tube, the first, spiral electrode being located initially within the distal end of the guide tube. A second, reference electrode is longitudinally dielectrically isolated and spaced from the first electrode, and each electrode is connected to a wire of a twisted wire pair running proximally within the guide tube. A physician inserts the distal end of the guide tube within the mother's vagina and cervix until the distal end of the guide tube makes contact with the head of the fetus. The drive tube is then extended distally so as to advance the end of the first, spiral electrode beyond the end of the guide tube and into contact with the epidermis of the head of the fetus. The drive tube is then rotated to screw the first, spiral electrode into the epidermis. The drive tube and surrounding guide tube are then withdrawn, leaving the first, spiral electrode attached to the fetal epidermis, the second, reference electrode in contact with the vaginal and cervical secretions of the mother. The proximal ends of each wire of the wire pair are then attached to a monitoring device. Further developments in this general type of apparatus are disclosed in U.S. Pat. Nos. 3,890,420, 3,910,271, 5,222,498 and 5,277,613, all to Neward, U.S. Pat. No. 5,671,736 to Pettit et al., and U.S. Pat. No. 5,680,859 to Urion et al., the disclosures of each of which are incorporated herein by reference.
It was recognized in U.S. Pat. No. 5,168,876 to Quedens et al., the disclosure of which is hereby incorporated by reference, that it would be desirable to employ a connector and circuit board assembly in the form of a reusable coupling device cooperatively configured to engage a connector at the proximal ends of the twisted wire pair located between the proximal ends of the twisted wire pair and the monitor. In Quedens, the proximal ends of the twisted wire pair are configured with a plug-type connector which is inserted into the connector of the coupling device, another cable then extending from the latter to a monitor. It was recognized in U.S. Pat. No. 5,199,432 to Quedens et al., the disclosure of which is hereby incorporated by reference, that it would be desirable to fabricate the connector at the proximal end of the twisted wire pair to be smaller in lateral dimension than the inner diameter of the drive tube, to facilitate withdrawal of the drive tube and guide tube thereover. Various connector contact configurations are disclosed in U.S. Pat. Nos. 5,373,843 and 5,632,274 to Quedens et al., U.S. Pat. No. 6,151,520 to Combs, U.S. Pat. No. 6,321,103 to Dowd et al. and U.S. Pat. No. 6,356,778 to Pirc, the disclosures of each of whichis are hereby incorporated by reference.
While the foregoing patents disclose various improvements in the state of the art, there remain a number of deficiencies with respect to the fetal scalp electrode assembly including a connector associated with the twisted wire pair, as well as to cooperatively configured coupling devices for receiving the connector.